Tear-A-Part is probably the best you pull site right now. Pick-n-Pull on 3300 S 500 W is OK, but the most expensive. Pull-n-Save out on 2100 S and 7200 W (I think thats the west) has the largest yard and take the longest to roll their inventory, but the yard itself is basically a mud pit and they rarely have a good selection, at least for the things I generally am looking for.
As for full service yards, I've had really good luck with Penguin Auto on 5600 W and about 2700 S.